Linq拡張メソッド重複レコードのフィルタリング

詳細
1.拡張クラス

   /// 

        ///  
        /// 
        /// 
        public class Comparint : IEqualityComparer where T : class, new()
        {
            private string[] comparintFiledName = { };

            public Comparint() { }
            public Comparint(params string[] comparintFiledName)
            {
                this.comparintFiledName = comparintFiledName;
            }

            bool IEqualityComparer.Equals(T x, T y)
            {
                if (x == null && y == null)
                {
                    return false;
                }
                if (comparintFiledName.Length == 0)
                {
                    return x.Equals(y);
                }
                bool result = true;
                var typeX = x.GetType();// 
                var typeY = y.GetType();
                foreach (var filedName in comparintFiledName)
                {
                    var xPropertyInfo = (from p in typeX.GetProperties() where p.Name.Equals(filedName) select p).FirstOrDefault();
                    var yPropertyInfo = (from p in typeY.GetProperties() where p.Name.Equals(filedName) select p).FirstOrDefault();

                    result = result
                        && xPropertyInfo != null && yPropertyInfo != null
                        && xPropertyInfo.GetValue(x, null).ToString().Equals(yPropertyInfo.GetValue(y, null));
                }
                return result;
            }
            int IEqualityComparer.GetHashCode(T obj)
            {
                return obj.ToString().GetHashCode();
            }
        }

2.使用

            this.ddlCompanyName.AppendDataBoundItems = true;
            this.ddlCompanyName.Items.Add(new ListItem(" ", "-1"));
            IList lst = GetCompanyList();
            this.ddlCompanyName.DataSource = lst.Distinct(new Comparint("CompanyID")).ToList();